Modern electronic systems typically include a data storage device such as a dynamic random access memory (DRAM), static random access memory (SRAM) or other conventional memory device. The memory device stores data in vast arrays of memory cells. Each cell conventionally stores a single bit of data (a logical "1" or a logical "0") and can be individually accessed or addressed. Data is output from a memory cell during a "read" operation, and data is stored into a memory cell during a "write" operation.
In a standard read or write operation, a column decoder and a row decoder translate address signals into a single intersection of a row (wordline) and column (bitline) within the memory array. This function permits the memory cell at that location to be read from or for data to be placed into that cell. The processing of data is dependent on the time it takes to store or retrieve individual bits of data in the memory cells. Storing and retrieving the bits of data is controlled generally by a microprocessor, whereby data is passed to and from the memory array through a fixed number of input/output (I/O) lines and I/O pins. According to current digital circuit technology, each I/O pin can access, at most, one bit of data during an operation cycle. This substantially limits the potential bandwidth or speed of the memory device.
Modern applications call on electronic systems to process data at greater speeds. In order for the systems to accord these demands, the system components must increase their processing speeds. One method to increase the processing speeds is to provide additional I/O pins on the system components. However, space limitations on both microprocessor chips and memory chips preclude simply adding more and more I/O pins. Another method to increase processing speeds is to decrease the cycle time for retrieving and storing data. Upper limits for increasing cycle speeds are set by current feature size (F) of the discrete devices from which the integrated circuit is composed. Modern photolithographic techniques, however, limit the size of the circuits that can be formed from semiconductor and other materials. At some point, the lithography cannot create a fine enough image with sufficient clarity to decrease the size of the elements of the circuit any further.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, it is desirable to develop other methods to increase the data throughput or data bandwidth without requiring an increase in I/O pins or further decrease the cycle times.